Aircraft typically include a plurality of flight control surfaces that, when controllably positioned, guide the movement of the aircraft from one destination to another. The number and type of flight control surfaces included in an aircraft may vary, but typically include both primary flight control surfaces and secondary flight control surfaces. The primary flight control surfaces are those that are used to control aircraft movement in the pitch, yaw, and roll axes, and the secondary flight control surfaces are those that are used to influence the lift or drag (or both) of the aircraft. Although some aircraft may include additional control surfaces, the primary flight control surfaces typically include a pair of elevators, a rudder, and a pair of ailerons, and the secondary flight control surfaces typically include a plurality of flaps, slats, and spoilers.
The positions of the aircraft flight control surfaces are typically controlled using a flight control surface actuation system. The flight control surface actuation system, in response to position commands that originate from either the flight crew or an aircraft autopilot, moves the aircraft flight control surfaces to the commanded positions. For example, during flight the pilot or co-pilot may position the primary flight control surfaces via one or more pilot or co-pilot user interfaces such as, for example, pilot and co-pilot yokes or control sticks, and pairs of pilot and co-pilot foot pedals. In particular, the pilot or co-pilot may control the position of the elevators, and thus aircraft pitch, by moving the pilot or co-pilot yoke or control stick in a relatively forward or rearward direction. The pilot or co-pilot may control the positions of the ailerons, and thus aircraft roll, by moving (or rotating) the pilot or co-pilot yoke or control stick in the left or right direction (or in the clockwise or counterclockwise direction). Moreover, the pilot or co-pilot may control the position of the rudder, and thus aircraft yaw, by translating a pair of right and left pilot or co-pilot rudder pedals using their right or left foot. It is further noted that in addition to being used to position the rudder, the pilot or co-pilot may also apply the brakes to the landing gear wheels by rotating a pilot or co-pilot brake pedal that may be integral with the rudder pedals.
Preferably, the pilot and co-pilot user interfaces described above are somehow linked so that when a pilot user interface is moved the corresponding co-pilot user interface moves at least substantially identically. For example, if the pilot moves the pilot control stick or pilot brake pedal, then the co-pilot control stick or co-pilot brake pedal will move at least substantially identically. There may be several benefits to linking the pilot and co-pilot user interfaces. One benefit is that the situational awareness of the flight crew is increased. That is, the pilot and co-pilot may each be able to closely monitor what the other is doing. Thus, in the highly unlikely event that one of them improperly positions their user interface, the other will be able to quickly recognize and correct this situation. Linking the pilot and co-pilot user interfaces can also be beneficial for pilot training.
Presently, pilot and co-pilot user interfaces are linked either mechanically, hydraulically, or electrically. The mechanical linkage systems and hydraulic linkage systems are typically rather complex and use significant numbers of components, which can undesirably increase overall system cost and weight, and concomitantly reduces system reliability. The electrical linkage systems, too, can be somewhat complex, which can also lead to increased system costs.
Hence, there is a need for a system that links user interfaces, such as those used in aircraft flight control systems, that is relatively less complex, relatively less costly, and relatively more reliable, than current systems. The present invention addresses at least this need.